Scrub brush



FIG. 1 is a perspective view of the scrub brush;

FIG. 2 is a front elevation view thereof, the left, right, and rear elevation views being identical thereto;

FIG. 3 is a top plan view thereof; and,

FIG. 4 is a bottom plan view thereof. 

CLAIM The ornamental design for a scrub brush, as shown and described. 